<!doctype html>
<html>
<head>
  <meta charset="utf-8" />
  <title>Your App</title>
  <link rel="stylesheet" href="https://cdn.bootcdn.net/ajax/libs/twitter-bootstrap/4.6.1/css/bootstrap.min.css">
</head>
<body>
  <!-- 自定义模板 -->
  <h1>自定义模板</h1>
  <div id="root"></div>
</body>
</html>